1. Field of the Invention
The present invention relates to a leisure vehicle, such as a personal watercraft (PWC) which ejects water rearward and planes on a water surface as the resulting reaction, or an all terrain vehicle (ATV). More particularly, the present invention relates to a throttle device of the leisure vehicle.
2. Description of the Related Art
In recent years, so-called jet-propulsion personal watercraft, which are one type of a leisure vehicle, have been widely used in leisure, sport, rescue activities, and the like. The jet-propulsion personal watercraft is configured to have a water jet pump that pressurizes and accelerates water sucked from a water intake generally provided on a bottom of a hull and ejects it rearward from an outlet port. Thereby, the personal watercraft is propelled.
The water jet pump is driven by an engine mounted in the personal watercraft. The engine is capable of changing an engine speed by operating a throttle operation means of a throttle device. Thereby, the watercraft cruises at a desired speed.
In general, there are two types of throttle devices, i.e., a mechanical-type throttle device and an electric-type throttle device. In the mechanical-type throttle device, an operation force (a force for operating a throttle valve) is transmitted to the throttle valve of the engine through a cable or a rod. In the electric-type throttle device, the throttle valve of the engine is remotely controlled in accordance with an electric signal. In the mechanical-type throttle device, by operating a throttle operation lever, the operation force is directly transmitted to the throttle valve of the engine through the cable. In the electric-type throttle device, a throttle position sensor detects an operation of the throttle operation lever, and an actuator provided on the throttle valve of the engine is activated in accordance with the electric signal, thereby causing the throttle valve to be opened and closed.
When the electric-type throttle device is applied to a watercraft with an engine having multiple cylinders, and in which a plurality of throttle valves are operated, the operation force of the throttle valves are favorably reduced. Nevertheless, since the throttle valve is not operated through the cable or the like, an operation state of the throttle valve at the time when the engine stops affects a state of the throttle valve when the engine re-starts.
In the electric-type throttle device, when the engine stops by turning on a kill switch, the actuator for operating the throttle valve electrically stops regardless of an operation state at that time, and the throttle valve remains under the condition in which the kill switch was turned on.
In general, the engine has its own response characteristic in acceleration. For this reason, when a rider quickly performs a throttle-open operation (i.e., an operation for opening the throttle valve) for the purpose of rapid acceleration of the vehicle, the throttle valve of the engine is quickly opened, and an open area of an air-intake port of the engine is rapidly increased, but an air-intake amount is not increased. This often leads to slow acceleration of the vehicle. In the engine having such a response characteristic, by performing the throttle-open operation more slowly than the above quick throttle-open operation, the acceleration becomes faster.
The present invention addresses the above described condition, and an object of the present invention is to provide a leisure vehicle having a throttle operation device in which a throttle state at the time when an engine re-starts is not affected by a throttle operation state at the time when the engine stops. Another object of the present invention is to provide a leisure vehicle having a throttle device in which a throttle valve is fully closed even when the engine stops by turning on a kill switch. A further object of the present invention is to provide a leisure vehicle having a throttle device capable of smoothly accelerating even when a throttle operation lever of the throttle device is operated at a speed faster than a predetermined speed.
According to the present invention, there is provided a leisure vehicle comprising: a drive engine; a switch operated when the engine starts; and a throttle device for controlling an engine speed of the engine, the throttle device including, a throttle operation means for controlling the engine speed of the engine, a throttle position sensor for detecting a throttle operation of the throttle operation means, a throttle valve for opening and closing an air-intake passage of the engine, an actuator for opening and closing the throttle valve, and a control unit for controlling the actuator for opening and closing the throttle valve according to a value of a detection signal output from the throttle position sensor; wherein the control unit is adapted to perform zero setting of the throttle valve such that the throttle valve is operated according to the value of the detection signal output from the throttle position sensor with the throttle operation means in a fully closed state, when the switch is operated.
According to the leisure vehicle so constituted, when the throttle valve is open, for example, about 20% of a full throttle state, under the condition in which the engine has stopped, the throttle valve is opened and closed according to the operation state of the throttle operation means when the engine re-starts, which will be described below. The throttle operation means is returned to a fully closed state when released at the re-start of the engine. When the engine re-starts by turning on the switch, the value of the detection signal output from the throttle position sensor is set to zero according to the operation state of the throttle operation means. According to the value (zero) of the detection signal, the control unit controls the actuator to cause the throttle valve to be fully closed according to the value (zero) of the detection signal. As a result, the throttle valve is opened and closed according to the operation state of the throttle operation means when the engine re-starts.
Preferably, the switch may be a main switch of the engine, because the main switch is typically operated when the vehicle re-starts, and therefore zero setting is typically performed.
Preferably, the switch may be a starter switch of the engine, because the starter switch is typically operated when the vehicle re-starts, and therefore zero setting is typically performed. This is advantageous in a leisure vehicle without the main switch.
Preferably, the control unit may be adapted not to turn on a start function of the starter switch for starting the engine until the zero setting of the throttle valve is complete regardless of an ON-state of the starter switch. Thereby, the engine can re-start under a preferable condition in which there is compatibility among the operation state of the throttle operation means, the operation state of the throttle valve, and the value of the detection signal of the throttle position sensor.
Preferably, the control unit may perform zero-calibration when the switch is operated so that the value of the detection signal output from the throttle position sensor becomes zero when the value of the detection signal is lower than a predetermined value with the throttle operation means in a released state. Thereby, when the engine re-starts, the value of the throttle position sensor is adjusted to be zero, and the engine can start with compatibility between the operation state of the throttle valve and the value of the detection signal of the throttle position sensor.
Preferably, the throttle operation means may be provided with a return means for setting the throttle operation means to the fully closed state. Thereby, the throttle device re-starts in a preferable condition in which the value of the detection signal of the throttle position sensor is zero and the throttle operation means is in the fully closed state.
Preferably, the throttle operation means may further include a movable member that moves according to the throttle operation of the throttle operation means, and the return means is a spring for returning the movable member to the fully closed state by a force of the spring.
Preferably, the leisure vehicle may further comprise a kill switch for stopping the engine, wherein the control unit is adapted to control the actuator to cause the throttle valve to be fully closed according to a signal indicating that the kill switch is turned on. Thereby, the engine re-starts under the condition in which there is compatibility among the value of the throttle position sensor, the operation state of the throttle operation means, and the operation state of the throttle valve. In addition, since the throttle valve is fully closed by turning on the kill switch, water or unwanted substances are prevented from entering the air-intake passage of the engine provided with the throttle valve.
Preferably, the control unit may be adapted to control the actuator to cause the throttle valve to operate at a speed slower than an operation speed of the throttle operation means when the throttle operation means is operated at a speed faster than a predetermined speed. Thereby, the throttle valve is opened and closed at the speed compatible with the response characteristic in acceleration of the engine, and consequently, the engine speed increases or decreases smoothly.
Preferably, the leisure vehicle may be a jet-propulsion personal watercraft.
According to the present invention, there is further provided a leisure vehicle comprising: a drive engine; a kill switch for stopping the engine; and a throttle device for controlling an engine speed of the engine, the throttle device including a throttle operation means for controlling the engine speed of the engine, a throttle position sensor for detecting a throttle operation of the throttle operation means, a throttle valve for opening and closing an air-intake passage of the engine, an actuator for opening and closing the throttle valve, and a control unit for controlling the actuator for opening and closing the throttle valve according to a value of a detection signal output from the throttle position sensor, wherein the control unit is adapted to control the actuator to cause the throttle valve to be fully closed according to a signal indicating that the kill switch is turned on.
According to the leisure vehicle so constituted, upon the kill switch being turned on, the air-intake passage provided with the throttle valve is fully closed. This prevents entry of water or substances into the air-intake passage. When the engine re-starts, the throttle valve is fully closed. Therefore, the engine re-starts under the condition in which there is compatibility among the operation state of the throttle operation means, the operation state of the throttle valve, and the value of the detection signal of the throttle position sensor.
Preferably, the kill switch may be an inversion sensor for detecting inversion of the watercraft. When the vehicle is inverted, the kill switch is turned on without being operated by a rider.
Preferably, the leisure vehicle may be a jet-propulsion personal watercraft.
According to the present invention, there is provided a leisure vehicle comprising: a drive engine; and a throttle device for controlling an engine speed of the engine, the throttle device including a throttle operation means for controlling the engine speed of the engine, a throttle position sensor for detecting a throttle operation of the throttle operation means, a throttle valve for opening and closing an air-intake passage of the engine, an actuator for opening and closing the throttle valve, and a control unit for controlling the actuator to cause the throttle valve to be opened and closed according to a value of a detection signal output from the throttle position sensor, wherein the control unit is adapted to control the actuator to operate the throttle valve at a speed slower than an operation speed of the throttle operation means when the throttle operation means is operated at a speed faster than a predetermined speed.
According to the leisure vehicle so constituted, the throttle valve is opened and closed at a speed compatible with the response characteristic of the engine, and therefore, the engine speed increases or decreases smoothly.
Preferably, the leisure vehicle may be a jet-propulsion personal watercraft.
The above and further objects and features of the invention will more fully be apparent from the following detailed description with the accompanying drawings.